The Insurance Institute for Highway Safety tested mini cars--cars like the Honda Fit--and the ratings were not favorable. This doesn't actually surprise me.
I had a 1999 VW Golf GLS, which was about the same size as many of the cars in this category, but it was around 2800 pounds, probably 600 pounds heavier than most.
When I was looking for another car, I considered the category because of the size. However, I couldn't find one with rear wheel disc brakes or other realistic safety items or features. I quickly abandoned the category as unfit, at least, for me.
Over the time I've owned the various Volkswagen models (1985, 1986, 1990, 1999, 2012), the size of the Golf has increased quite a lot, and yet, it's still not a huge car on the outside, even though the inside is much bigger than you would expect.
It's obvious from the weight that there is much more in the car than the engine and transmission. For small cars, Volkswagen has often done more than the typical economy car maker to safeguard passengers. The passive knee pad was an early innovation that seems to have gone away but had its time and place.
I'm going to be rude because it seems as though someone gets behind the wheel of an SUV and loses their ability to think. They seem to be more aggressive (especially early Ford Explorer drivers), and do stupid actions that they wouldn't normally do with anything else, thinking that the vehicle was made for ridiculous maneuvers that you would only see in movies.
I've driven one Jeep Grand Cherokee, one Chevrolet Suburban (which hardly seems an SUV), and a Jeep CJ5. They seemed better in the slow lane, as the center of gravity was too high to keep the vehicle steady in curves and turns.
So, taking a mini car like a Mazda 2 up against a Jeep Grand Cherokee, which isn't all that steady isn't for the timid. (Remembering someone telling me that his friend's mum took their Hummer H2 (not the craptacular GM platform) through a fast food drive-thru and ran over a number of things makes me wonder if the H2 would just crush the Mazda 2 in traffic.
If the Mazda 2 could have been configured with safety gear, I really would have considered it. However, it and the others were too much like the flimsy European cars of the 1970s, like the Renault 5 or Fiat 128. They may pass government safety standards but the federal government has been slow to move those standards in order to pacify the auto industry.
I wonder what sort of results the Germans would get in the same tests. Audi, Mercedes-Benz, and Volkswagen all have much smaller cars that never arrive in the U.S.A. I'm sure it's difficult to make money on them, so they will likely never see this country.